the templar's would react very hostile. I could see more radical ones pushing for a right of annulment(purge their mage populations). others would probably look towards the chantry for direction. a few might fall to the influence of Krorne given the mindset.
the chantry would probably be crippled on the grander stage, while local chantries focused on quelling any small chaos incursions and recruiting people to bolster the number of Chantry templar's.
the circle would probably have a fairly divided response. on one hand, WHF daemons are both more dangerous in terms of overall potential for corruptoon and less dangerous since you can pit the different chaos gods against eachothers to balance out there influence over the mage in question and their minds wouldn't be completely consumed like with fade spirits. ultimately there will probably be a split between historical apostates and chaos gods worshippers
Tevinter probably suffers a few disasters and cult infighting before parts of Minrathus fall to daemon cults, before being expelled by mages who develop counter methods against chaos. hard to predict where things go from their until I've played Veilguard, though to be frank I'm not sure how much world building the linear, no respect for meaningful decisions made in previous entries mess will be.
there is also of course the Qun to consider. they would probably use this to seize Seheron, but the Qun is anti-thetical to chaos gods. there going to recall their forces hard to crush the barest sparks of Chaos in there lands before dispatching spies on a fact finding mission before using that information to determine which greater Daemon they consider most offensive to the Qun and dispatch the Arishok to fuckup that Daemon. my money is on Kaeros.
Lyrium is just a huge question mark of course. same with Darkspawn. of course if the immaterium is beginning to supercede the Fade than you don't just have chaos gods now do you? Lyrium is alive, and kinda fungussy in my opinion. if Gork and Mork start causing Orks to Grow out of Lyrium, then the Darkspawn Mite be in for a he'l of a krumpin, along with the rest of thedas.
